I know some fans had a hard on for Jonas (I am not one of them). Sure Jonas has a high return potential, but he also has the same high risk bust potential.
I am amused that the OP puts that much emphasis on 2nd round picks.
They also saw the chemistry between the players. Rather than drafting a foreign prospect like Jonas Valanciunas - which was heavily considered - the team knew that Irving and Thompson were already close friends, could relate with one another and would be able to go through this process side by side.
After Irving was picked, he was ushered into the media room and his press conference dragged on throughout several selections. As the fourth overall pick was announced, Irving was being asked a question, but kept leaning over to the television to see who would be joining him in Cleveland. After seeing Thompson was the selection, Irving smiled and his eyes lit up.
"I'm really looking forward to it," Irving said. "Tristan is a great friend of mine, and just having another fellow freshman being drafted to Cleveland and playing with him, I'm really excited. He's also a young player, and having somebody alongside you that will go through the rookie ups and downs with you, it will make the transition into the NBA that much easier."
http://www.hoopsworld.com/Story.asp?story_id=20262